


Under the Stars

by tsukithewolf



Category: Undertale (Video Game)
Genre: Cute and stupid and fluffy and sexy, Future AU, Gender ambiguous Frisk, Other
Language: English
Status: Completed
Published: 2016-09-14
Updated: 2016-09-14
Packaged: 2018-08-15 00:34:42
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 7,984
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8035162
Author URL: https://archiveofourown.org/users/tsukithewolf/pseuds/tsukithewolf
Summary: Frisk had waited a long time to seduce Sans. They never realized Sans was just waiting.





	Under the Stars

**Author's Note:**

> So I wrote this a long time ago before I actually started writing the Future AU, so you'll notice the timelines and the story does not add up with the Future AU. Consider this Future AU.1 Anyway I still REALLY like how this turned out, so I thought I would share it anyway.

Tonight, Frisk had a plan. It was one that they had been developing for the past couple of weeks ever since they had turned of legal age. Tonight, they were going to seduce Sans. And tonight, they were finally going to have sex. Which, admittedly, isn’t a very grand plan, but Frisk had been waiting patiently for years now. Sans and Frisk had been dating since middle school. In reality, they hadn’t even agreed to anything. It was something that just happened. It was something that just felt right to Frisk. They attributed it to that same reason why they had instantly trusted Sans the moment they had met him. It was just something that happened. But because nothing was ever explicitly stated, Frisk hadn’t known the boundaries. So they hadn’t pushed them at all. Things stayed relatively platonic (despite many of their friends thinking that they’d had sex a long time ago).  

In the meantime, their relationship had only changed some over the years. The kisses on the cheeks became snuck kisses on the mouth. Holding hands had more meaning behind it. Little platonic things finally crossed a line and, despite not actually being any different, felt like a big step to Frisk. Although, to be honest, they weren’t satisfied. There had been days they had stared at Sans and daydreamed about climbing in his lap and kissing the daylights out of him. When Frisk woke up cuddled against the soft heat of their boyfriend, they considered sliding a thigh between his splayed legs to see what they would discover. And secretly, they sometimes did. Just to see what it felt like to be straddling his thigh.

It’s very frustrating, on Frisk’s part, wanting to have a sexual relationship when they weren’t even sure if Sans was into that kind of thing. It wasn’t something that either of them had talked about, and Sans had always laughed off whenever it was brought up among nosy friends. Sure there had been signs about it. Sans woke up with erections quite often. Frisk knew that this was a normal thing. It was just how things worked. So they couldn’t even really count that. But sometimes Sans got erections from other things. Things that, thinking back on, Frisk realized had been triggered by them. Such as their swimsuit. And walking into his room after a shower with their hair still wet and their clothes sticking to their body because they hadn’t dried properly. And things that hadn’t made sense. Like when they were out eating together. Or at the park.

Eventually Frisk had asked if they were really together. And Sans had said yes, they were in fact dating. But Sans hadn’t actually pushed their relationship. The last time Frisk remembered actually tasting Sans had been on their birthday a couple months back. And that had only been with making out. Frisk had seen quite a number of parts of Sans (although not everything), and Frisk wanted to actually explore the skin they saw. They wanted to figure out what spots made Sans develop that delicious blush that so rarely appeared on his face. They wanted to run their fingers through the hair on his stomach that would lead down into his shorts. They wanted to know the scent of Sans’s arousal and the taste of him on their lips.

But even more than all that, Frisk wanted Sans to touch them. His fingers would sometimes brush their stomach or ribs, but he never lingered. The little touches would light Frisk’s skin on fire. They wanted Sans’s hands and mouth on them. They had a brief experience of him mouthing at their neck, but that hadn’t lasted. Frisk could still imagine the stubble as it scraped across their collarbone. There had been many times that they had fingered themselves and had imagined Sans was doing it instead. Toys, sometimes, just weren’t enough. And they could get boring.

So tonight, Frisk had a plan. Sans wouldn’t initiate anything, so Frisk would be the one to do so. Sans’s family was out of the house for the night. Frisk’s parents would not be bothering Frisk at all. Sans didn’t have a job to do tonight. This night would be only theirs. And Frisk was determined. They had cleaned themselves up, taken a shower, and had dried their hair before changing into their own “battle armor”. It was lingerie in Sans’s favorite color blue. The underwear was small, but tasteful. And tauntingly opaque.  Likewise with the actual top. Frisk didn’t have much in terms of a bust that usually was meant to fill out these girly baby doll tops, but it worked out. It was just decoration anyway. Frisk felt cute, but sexy.

Now if only they could manage to work up the courage to step out into the living room where the unsuspecting target was waiting.

==

==

Tonight was one of those rare nights where Sans had the house to himself. So naturally, Frisk was spending the night. Which was all well and good because Sans actually preferred to have the kid’s company. However, it was also somewhat distracting because it had been a while since he’d had “alone time” and having Frisk around wasn’t helping. And that was still such a strange concept to him because he could still remember enough of his last life to know that sex wasn’t a part of it. He even remembered finding it baffling and gross. Now, though, the thought of being in Frisk (and sometimes vice versa) always got him going.

It was a damn shame, then, that Frisk so far hadn’t seemed interested. Not that Sans had tried to initiate anything, but Frisk never showed signs of actually wanting to  _ do _ anything with Sans. He wasn’t even sure if Frisk had a sex drive. And wouldn’t that just be a kick in the ass if Sans was almost constantly horny and Frisk just wasn’t interested?

The thought always made him groan.

So Sans never pushed anything. Frisk would come to him in their own time. It’s not like he hadn’t given them enough hints that he was, in fact, very much interested in sex with them. Hell, Frisk drove him crazy every time they slept in the same bed together. It was almost torture seeing them wear those thin pajamas to his bed. He could see a number of curves on their body. Especially when they didn’t dry themselves properly.

He wondered how his past self had handled his Frisk. It certainly seemed like in a lot of the pictures that were taken that he was very close to Frisk. There were even some of them kissing, which was nice to know even though he wasn’t sure how kissing a skeleton worked. For some reason he could remember watching pornography with the other Frisk, but Sans hadn’t been interested in sex then. Was it for Frisk’s benefit then?

Sans flipped the channel on the television as he mused to himself. There was nothing particularly good on. Frisk had been in the bathroom a long time, but he wasn’t going to judge. Maybe they had fallen asleep in the shower. Sans did that a lot. He wondered if he had time for a quick wank. He leaned his head back on the couch and considered it. The thought of Frisk catching him was appealing.

He heard the door open then. He flipped the channel again. Some kind of cooking show. Maybe they should watch a movie. “hey frisk, is there anything you want to watch?” He turned to Frisk and froze. Their face was filled with determination, but their body was shy. They were wearing probably the thinnest material he had ever seen on them, but it instantly interested him. Because that type of clothing was made to catch someone’s interest sexually.

And Sans was very interested.

His eyes roamed up from their bare legs, pausing on the tantalizingly small and opaque underwear, before traveling up and across the top. Frisk didn’t have much of a bust, but the top was the type that it didn’t matter. It was Sans’s favorite color blue and had frills traveling down it. Finally he allowed his eyes to land on their face. Frisk was blushing slightly, but smiling softly.

Sans slowly turned back to the television and blinked. This was...unusual. He was pretty sure Frisk didn’t own any lingerie, let alone anything that looked like that. This was clearly his imagination. Which meant he probably fell asleep on the couch. Funny, though, because he had never exactly been aware in his dreams before. This was a twist.

“...guess i fell asleep.” Sans muttered to himself. Frisk frowned, feeling slightly discouraged. Sans, other than looking them up and down, hadn’t reacted. And now he thought he was dreaming? No, they couldn’t get discouraged! They were determined. Tonight was the night, dammit, and they would seduce Sans! Phase one may have failed, but Frisk knew how to flirt! Maybe they could use this situation to their advantage.

Frisk took a breath before walking over to the arm of the couch and sliding onto it. They straddled it, sticking their assets out for Sans’s attentive eyes. “Do you...dream a lot about me?” They asked quietly. They ran a hand slowly up their own thigh, mentally cheering to see Sans’s eyes follow the same path. Frisk pulled their leg over so they were kneeling on the couch. They crawled the short distance to where Sans was sitting before placing a hand on his chest. They could feel his heartrate picking up.

Frisk looked down, and then at him through their eyelashes. “Do you...often want me to look like this?” They tilted their head to the side, allowing their longer hair to brush over their collarbone. Frisk ran their hand up Sans’s chest to his neck. “Do you...dream of me doing this to you?” They breathed, leaning closer to his ear.

Sans’s eyes fluttered shut as he took a steadying breath. Okay, yeah, no. This wasn’t a dream no matter how much it seemed like it. The Frisk in his dreams was sexy, but usually it was just sex. And it never felt this realistic. Which could only mean this was real. And Frisk was pretty fucking good at being a tease if the fingers drawing circles on his chest and shoulders were anything to go by. But Frisk had always been like that, Sans remembered. They liked to flirt and always have. It had been hilarious seeing the situations Frisk got themselves out of just by flirting. But this...this was actual flirting. And Sans could play ball.

“yeah.” He slid a hand around their waist and tugged them into his lap. Frisk looked slightly surprised, but delighted. If they were going to play this up as a dream, Sans would go along with it too. Confidence was all he needed here. He would trust that Frisk would stop him if he went too far. But he doubted much anything he would do tonight would be going “too far”. “i’ve definitely wanted you doin’ this to me. and lookin’ like that too?” He grinned and pressed a kiss to Frisk’s sternum. They gasped at the touch. “happy birthday to me.” He finished, letting his lips brush against their skin. His hands fiddled with the thin strips of satin elastic that were part of Frisk’s waistband. If he wanted to right now, he could slide them down and off...but that wouldn’t be any fun. So instead his fingers danced along their hips to−

“oh.” Sans smirked and Frisk felt their face flush some. “naughty underwear.” Sans murmured as he boldly grabbed two handfuls of Frisk’s bare bum. Frisk jumped and immediately wrapped their arms around Sans’s neck. This...was not the way they were expecting things to go. Sans kneaded them as his lips found their neck. Frisk shivered, hand finding his hair.

“S-Sans...” They murmured. His tongue traced a line up their pulse. They were losing control of the situation fast, and a part of them wanted to just be swept away in it. The plan, so far, was succeeding, but they had items on their list. They tugged Sans’s hair until he pulled back with a slightly annoyed look. Frisk wasn’t having any of it. “Kiss me.” They commanded.

“bossy.” Sans muttered.

“Need you.” Frisk corrected. Sans paused, not expecting that answer.

“you’ve had me.” He told them before pressing forward to kiss them. Frisk responded eagerly and slightly desperately. Sans’s fingers danced up their back, making small circles into the skin. Their skin prickled at his touch even as they deepened the kiss. Man, it had been way too long since he’d made out with Frisk. And that was a big regret now because Frisk was a damn fine kisser. His nails dug some into their back as Frisk’s hands dove under his shirt and pushed up. His skin seemed to awaken at the touch of their fingers. He pulled back for a breath and to haul his shirt off, before diving back in for another kiss unable to resist.

Frisk pulled back again, gasping slightly. Sans took in their dark dilated eyes. There was a desperation to them that he didn’t understand, but didn’t quite like. “Not enough.” Frisk whimpered. “More. Please.” They kissed him again, hands tugging at his shorts. Sans would’ve gladly rid himself of those too, but he had priorities.

Frisk blinked in shock as suddenly their positions were reversed. They were thrown onto their back, Sans kneeling between their legs. He paused for a moment, smiling as he took in the view. “sexy.” He stated, making Frisk flush lightly. They closed their legs some, but couldn’t all of the way considering Sans was in the way. Sans leaned down and kissed them slowly. Frisk tugged at his side, urging him to press his body to theirs, but he refused. Frisk wanted faster, but Sans continued his slow passionate kiss until Frisk slowed their own pace to match his.

When they were significantly calmer, Sans pulled away enjoying the sight of their saliva glistening on their lips in the low light. That face was definitely one to remember. One thing his past self probably didn’t have was memories of Frisk looking thoroughly ravished. Pity that.

“slow down, buddy.” Sans told them, pecking their lips again. “we have all night.”

“Sans.” Frisk said again, and Sans really loved hearing his name on his lover’s lips. They had been friends for years, and probably even longer than that. And Frisk had a way of saying everything they wanted from Sans just by saying his name. He suspected part of it was his history with Frisk. He just knew them. And right now, he understood their desperation. Even now there was a low-burning fire in his bones ready to turn into an inferno and consume the both of them. The hungry thought of just ripping that thin underwear off of Frisk and just plunging into them was almost too tempting. But he wouldn’t do that. Not this time, and maybe not ever. Right now, he wanted to make this good. After all, it was their first time together. And he had waited a hell of a long time.

“relax.” Sans coaxed, pressing kisses along their jaw. He slowly allowed himself to add his weight to Frisk, bringing their hips together. Frisk mentally thanked the fact they were practically the same height as they shared another slow kiss. Their skin itched for more and faster than the speed they were going. They clawed at Sans’s back a little too roughly, causing him to grunt. They whispered an apology and stroked the abused skin. In return, Sans slowly began to grind their hips together. Frisk gasped at the hard line of his erection, knees coming up to clamp onto his hips. It was too slow. Frisk felt like at any moment this would be over before it really began. Someone was going to walk in and ruin it. It was all too perfect. The comedic timing at its best. Frisk couldn’t help but get the feeling that this will be the only time they would be able to do this. After all, last time they only had Sans for one blissful night before they had to...wait...

“frisk?” Sans asked, pausing in his ministrations to see his lover distracted. They were frowning at some thought, making ice run through his veins. Had he done something wrong? Was something wrong at all? Shit, maybe he shouldn’t have gone for the hickey. It was a possessive thing and−

“Have we...done this before?” Frisk asked, their voice unreadable.

“no?” Sans answered. Frisk gazed into his eyes, but they seemed somewhat glazed as if remembering something. Sans recognized that look, but when, or rather  _ how _ , the hell would he have had sex with Frisk in their past lives? He had no memory of it, but little things seemed to seep through the cracks for Frisk. They weren’t aware that this was another life, though, and Sans was determined to keep it that way.

He pressed a hard kiss to their lips before pulling away to grin at them. “now who’s dreamin’ of who?”

It seemed to do the trick as Frisk focused back on him. Their hand came up to cup his jaw, thumb skating across the stubble there. “I always dream of you.” Sans wasn’t sure how Frisk could say things like that with a straight face. He looked away, feeling his cheeks burning slightly. It was as close to “I love you” as either of them had gotten. Frisk quickly roped his attention back as their hips ground against his, causing him to elicit a gasp. They grinned deviously at him. “Want me to show you how?”

“definitely.” Frisk pulled him down into a heated kiss, teeth nipping at his lips as they thrust their hips upwards. They rolled as Frisk tried to switch their positions, but it only caused them to topple off of the sofa. They both gave surprised yelps, hitting the ground. Sans cursed as Frisk landed hard on him, just barely missing a knee into his groin.

“Sorry!” Frisk apologized quickly, sitting up to look Sans over. He was rumpled and a little sore, but still good. He waved off their concern.

“couch probably isn’t the best place for this anyway.” He admitted. He definitely didn’t want to have sex on his family’s couch. He wasn’t sure if he would be able to look his dad and brother in the eye if he did.

“But this!” Sans gaped slightly as Frisk seemed to magic off his shorts. When had they even unbuttoned them? He hurried to adjust his underwear properly more out of reflex than anything. Frisk was smirking as they lowered themselves down between his legs. Attention caught, Sans watched as Frisk kissed along his thigh getting closer to exactly where he wanted them to be.

“hey frisk.” Frisk paused, the tip of their tongue tantalizingly close to the tent in his underwear. Sans gathered what little self-control he had to continue, “i’m totally all for that...but not here.” Sans pressed a bare foot to their stomach and pushed them away from him and onto their back. He grinned cheekily and climbed to his feet as they glared at him. He grabbed his discarded clothes and allowed himself to take in the frumpled sight of his lover. He quirked an eyebrow as he approached the bedroom. “comin’?”

Frisk hurried to their feet and smoothed down their top before following. They had only been a few seconds behind, but somehow Sans had managed to get his underwear off and was splayed rather unashamedly across his bed. Frisk froze, taking in the image of him as their heart jumped. Sans yawned and stretched widely before relaxing again. His smile was lazy, but his eyes were seductive. Frisk could see the bright blue eyes from where they were standing. They closed the door behind them.

“Tease.” They accused.

“says the one dressed like that.” Sans shot back, his hand moving to stroke himself. He stared hard at Frisk, making them flush as they realized that their appearance was turning him on. Well, of course! They had planned that after all! Two could play at that game. Frisk pressed their back to the wall and tilted their head so the hickey forming on their neck was visible. They ran a hand from their neck, down the middle of their chest, and towards their stomach. Sans’s eyes tracked the movement eagerly, filling Frisk with self-confidence. Their finger skated the band of their underwear, pushing it down only a little bit. They saw Sans’s hips jerk in his hand as Frisk’s own sneaky hand slipped into the underwear to touch themselves.

Frisk had done this many times before to themselves. They already knew exactly what they liked and how they liked it. So they spread their legs and allowed themselves to be swept away by familiar movements. The underwear was constricting and they honestly wanted to get rid of it, but Sans was gaping a little at what he was seeing and that made it all worth it.

Sans bit his lip at the delicious sight of Frisk working themselves in front of him. He had only done it himself to keep his energy up but now? Fuck, he didn’t even need a hand. And this totally wasn’t fair. It was like someone was holding a buffet right in front of him when he was starving...and Frisk was eating it without him.

He groaned softly before giving in. “alright, you made your point. get over here.” He commanded. Frisk didn’t stop right away, though, allowing themselves to slow to a more natural stop. Their chest heaved a bit as they pulled their hand out and licked what was there. Sans shivered and held a pleading hand out to Frisk. They grinned and finally ( _ finally! _ ) joined him on the bed. Sans didn’t stop as he pulled them into a hungry kiss.

Their show had apparently worked in driving Sans mad as his hands scrambled to touch every part of Frisk that they could. The top came off finally, and Frisk diverged themselves of the underwear soon after. It had honestly become kind of painful to wear. Finally they were both naked. Frisk ran their fingers through Sans’s chest hair and kissed a nipple. Sans’s hands grabbed Frisk’s thighs and pull them forward and apart so they were practically sitting in his lap. Frisk shuddered at the bare erection pressing against them, wiggling some for the friction of it. Sans sighed in pleasure.

“fuck.” Sans’s head thumped back against his pillow. His eyes trailed up Frisk’s bare form to their flushed face. He had only dreamt of this before, but actually experiencing it was a lot better. Kind of awkward in their movements, but still a lot better. He arched against them, feeling the sweat between them slicking the movement. A wank before this honestly would’ve been a blessing because Sans wasn’t actually sure he would survive to get to the main attraction. “you’re drivin’ me insane, frisk.”

“Me too.” Frisk admitted breathily, still moving against him. Their head was tilted back with whatever they were thinking of. Were they imagining they were riding him? Frisk moaned softly as Sans’s cock twitched at the thought. He cursed again. Their entrance was already so close to him. This was great, but he needed some kind of heat. Something solid. Or, at least, something to plunge into. Unless Frisk had other ideas? Because they seemed pretty content with just grinding to orgasm.

“h-hey, pal.” Sans muttered, grabbing Frisk’s hips to stop them. Frisk whined a little, pouting at their fun being interrupted. Sans huffed a laugh, smiling. “this all you want to do tonight? cuz, y’know, if it is that’s cool. let’s keep goin’. but...i can’t help but think you gettin’ all dressed up wasn’t just for this.”

Frisk considered his words as they glanced down at themselves. They were throbbing, already fairly close to orgasm. They...weren’t going to last long. But they still had much that they wanted to do with Sans. They shot him a somewhat desperate look. Sans tipped them so they were both laying on the bed and pulled Frisk close to kiss them slowly. He nipped gently at Frisk’s lips before sliding his tongue in. The fire in Frisk’s chest dulled to a warm burn as they melted into his embrace.

When Sans pulled away, he pressed another quick kiss to their lips before leaning his head against theirs. “frisk, i told you. we have all night.” He grinned a little. “if one of us comes, we can just wait and go again in a little while.”

“I want you in me.” Frisk declared quietly. Sans kissed them again for that quickly.

“y...yeah. sounds like a good plan.” He agreed.

“If we have all night...then can I try something?” Frisk asked.

“yeah, of course.” Sans agreed readily. Frisk pushed him onto his back then before shifting between his legs. “oh.” He said, realizing.

“Oh.” Frisk mocked playfully. Sans nudged their thigh for that. In response they grabbed his cock and gave a quick bold lick. Sans’s hands automatically clenched the bedsheets. Frisk paused, suddenly shy. “Tell me if...something isn’t good.”

“frankly, buddy...” Sans murmured, “i’m not sure you can do anything wrong here.”

Frisk huffed. “Then tell me if I do something you particularly like.”

“gotcha. but...gotta warn ya...i will probably come.”

Frisk grinned. “Good.”

“shit.” Sans muttered to himself as Frisk set to work. They were cautious at first, testing his reactions, but as confidence built they were able to draw more sounds from Sans. And they reveled in hearing his moans, feeling his thighs clench around them, tasting his sex on their tongue. Their hands were not still through this. They allowed their hand to explore the skin available, touching Sans in places Frisk had only dreamed of. And for the most part, it received a positive response. They wished that they had some lube.

“frisk.” Sans warned. He could feel his muscles tightening as orgasm approached. It was somewhat embarrassing only last this long. Despite being lazy, he actually had a fairly decent sexual stamina. Frisk gave a rather pointed suck as they spread his legs further. He arched into their mouth, the heat of it too much, and finally released with a moan. Frisk jerked back in surprise and swallowed what they had. They licked their lips and, as Sans recovered, met his eyes.

Sans grinned wearily. “you gotta little something.” He motioned to his own face. Frisk grabbed Sans’s stray underwear, not caring, and quickly wiped off their face. “gross.” Sans chuckled.

“That wasn’t...nearly as sexy as I thought it would be.” Frisk admitted, rubbing at their sore jaw.

“maybe not for you.” Sans said. Frisk idly played with themselves. They weren’t as turned-on anymore. For retribution, they kissed Sans. He made a face at the taste of himself but accepted the kiss. Frisk pulled away then and laid back onto the bed. Sans closed his eyes, relaxing into the feeling of endorphins running through his body, before he opened his eyes again and sat up. He barred Frisk between his arms. “want me to go down on you, then?” Frisk had always said in the past life that lips and tongue were a turn-on for them so...

“Not yet.” Frisk said, tugging him down into another kiss. He went willingly, leisurely deepening the kiss. He sat up and pulled Frisk into his lap before pulling away from the kiss. He instead chose to lick and nip a trail of kisses down the column of their neck and to their chest.

“why not yet?” He murmured curiously before pressing a hand between their shoulder blades. Their chest arched forward as Sans latched onto one of their nipples. Frisk shivered and gripped his shoulders, running fingernails over his back.

“It’ll take me...longer to get worked up again.” Frisk panted softly, massaging his shoulders in encouragement to his ministrations. Sans rolled the bud between his tongue and teeth as Frisk shifted until they were kneeling over his lap. Sans could feel the wetness trailing between their bodies. He was certain that if he played with Frisk just a bit more down there, they would be coming thanks to him. It was tempting to go through with. Very tempting. His free hand rubbed their thigh as he switched to sucking on the other nipple.

“so?” He asked, kissing their ribs. “all night, sweetheart.”

Frisk’s nails bit a little into his arms at the nickname. Sans didn’t use pet names like that for them often. Frisk’s hand slid up and down his arm. “Sooner rather than later.” They told him.

“sex?”

“Yes.” Frisk had waited a long time for this. If they had all night, then they had all night to explore other things. But they had priorities that they didn’t want messed up. They were still wary of any kind of interruptions.

Sans’s hand slipped up to cup them, a sly finger moving to rub curiously at Frisk’s entrance. Sans moaned breathily against their chest as Frisk’s body clenched at his touch. He was excited to explore deeper. “think you can handle fingering?” He asked.

“I do it all the time to myself.” Frisk assured him. Sans was still recovering from his orgasm, but  _ damn _ did that make his arousal spike again. The image of Frisk fingering themselves was enough to kick start his drive again.

“that’s...a real delicious thought sweetheart. but.” He pulled back, grinning in amusement, “i meant could you handle it right now?”

Frisk blushed some, realizing what they had given away. They shifted against his prodding fingers, tilting their hips encouragingly into his hand. “Yes.” They decided, more craving having his fingers inside of them than worrying about coming. Sans wrapped an arm around their waist and encouraged them to tilt backwards. With his help, they landed on their back on his soft bed. He gave a quick teasing kiss to their sex, swiping his tongue once before rolling on the bed to the side table. Frisk felt a whimper building again in their throat, missing his heat.

“Sans.” They called.

“just a sec.” He told them, digging through the dresser. “wanted to show you somethin’ tonight. now seems like a good time.” He pulled a remote out of the drawer and pressed a few buttons. Frisk gazed wide-eyed as the walls and ceiling of the room seemed to turn transparent. Sans lived fairly far out from normal cities, so the stars were always visible at his house. Frisk instinctively went to grab the blanket to cover themselves, but Sans stopped them. “don’t be  _ star- _ tled.” He winked. “it’s just one way. nobody can see in.” He kissed up their arm slowly until he reached their neck. Frisk let out a sigh as they tilted their neck into his lips. “s’almost like we’re outside...” He murmured into their skin.

Frisk gripped Sans’s shoulder and ran a hand down his chest, scratching lightly. “When...?” They murmured. They were having a hard time keeping their eyes open, but they couldn’t help staring up at the stars above them. They could see the nearby moons and a few of their cities. The galaxies swirled above them. Frisk barely paid attention to the small pop that signified Sans was opening the lubricant they had set up on the side table.

“recently.” He told them, kissing and licking his way down Frisk’s chest. “thought it’d be cool.” Frisk gasped as he nipped one of Frisk’s nipples. He lathed it with his tongue as a hand trailed lower. Frisk lifted their legs and hips as Sans’s probing finger found their entrance. Frisk’s body clenched at the sensations.

“Sans...!” They tugged gently on his hair in warning. He kissed them instead. Frisk whimpered at the intrusion, shifting their hips to allow him to go deeper and trying to help him. They tried not to focus on what was going on between their legs and instead on the ceiling. They pulled away from Sans, but he followed with a firm lick to their jaw. Frisk’s hips jerked. “No no no!” They whispered. “I’m gonna...!”

Sans stopped immediately. Frisk whined covering their face. “frisk?” He asked.

“I’m close.” They admitted.

“need to stop?” He asked. He took in Frisk’s panting visage. The flush on their cheeks was delicious. He closed his eyes briefly to feel their body clench again around his fingers. Frisk nodded weakly. He kissed their knee and gently pulled out. He pulled their body to his and kissed their cheek. Frisk tilted their hips against him, kissing his neck. Sans hummed and closed his eyes. He could feel the tension in Frisk’s body as they resisted the urge to finish themselves off. He sighed. “there’s time, pal.” He repeated.

“Not yet.” Frisk said. Their hand traveled down and gripped him. He shifted so they had a more comfortable grip.

“lube.” He muttered as they sucked on his neck. Frisk paused briefly to get the lube again. They added it to their hand before returning to what they were doing. Sans hissed with pleasure. “s’not much, nng, fun if i’m the only one who...comes twice.” He told them.

Frisk smiled again his collarbone. “There’s time.” They teased.

“good point.” He said.

“Ready.” Frisk told him.

“yeah, alright. just let me...” Frisk released him and worked instead on getting comfortable. They stared again at the stars. It really did feel like they were outside, but the cold wasn’t quite there. Sans blocked the view, grinning down at Frisk. Frisk smiled back as Sans lifted their legs. Frisk sat up to kiss him again before he positioned himself. “did i mention,” Sans asked, “how great you look?”

Frisk wiggled some, flushing with pleasure. “Stop.” They told him.

“i would make a joke,” Sans told them as he carefully pushed forward, “but the timing isn’t... _ pun- _ ctual.” Frisk laughed and Sans pushed in a bit faster making them gasp. He grinned, pleased.

“Jerk.” They smacked his arm.

“it worked, huh?” Sans glanced down at where they were connected. Frisk closed their eyes at the feeling. It was strange and wonderful having Sans inside of them. A craving that they had been feeling gnaw at their belly seemed full now, but a fire was raging in them. They wanted more with their edge already so close. They weren’t sure how long they would last or if Sans would even be able to finish. They opened their eyes again as Sans’s hand ran along their trembling thighs, massaging them. Sweat coated his face, his pupils blown wide with his arousal. Frisk admired his restraint even as they felt his hips strain to hold still. They clenched around him and a soft moan punched out of him. They had successfully reacquired his attention.

 

“Sans.” They murmured and reached for him. Sans glanced down at the connection between them briefly before he leaned forward to kiss them. Frisk made a small noise in the back of their throat as their body bent a little more in half to accommodate the movement. Their hands ran into his hair as he kissed them sweetly. They grinned a little as some of his sweat dripped onto their face.

“i’m gonna move, ‘kay?” He asked as he pulled away with a peck to their chin and trailed his lips to the curve of their jaw. Frisk only nodded shakily and hooked their legs over his hips. He was slow in his movements as he muttered something wordlessly against their skin. Frisk pulse seemed to spike with each movement, their heart jumping despite the awkward sensations. They liked it, but at the same time their body seemed confused at how overwhelming everything was. Their arousal dimmed slightly.

This was strange, Sans decided, as he shifted up onto his hands. Frisk’s eyes popped open at his movement, a torn frown on their face. He smiled questioningly. Frisk shook their head quickly and Sans stopped, heart stuttering unpleasantly.

“bad?” He asked.

Frisk quickly shook their head again. “N-no, just . . .weird.”

“right?” Sans grinned.

“Can you . . . talk?” They asked quietly, blushing. As delightful as the sounds their bodies were making were, it felt strange to have their voices suddenly quieted after talking with him through the entirety of their activities thus far. It left too much room to think.

Sans’s eyebrow quirked, interested. “sexy talk?” Frisk looked to the side, but they didn’t deny it. Sans decided to tease them more, “make me do all of the work? how about we trade?”

“Trade?” They asked.

Sans glanced down between the two of them. The sight of their connection spiked his arousal again. “why don’t you give me a show . . . and i’ll give you some commentary?”

“How?” Frisk asked before their breath caught in their throat at Sans’s shifting. They clenched around him automatically. Sans barely bit back a groan and resisted a responding thrust that his hips wanted to act upon.

“make it fun.” Sans murmured, trying to think through the lustful haze in his brain. “you’re usually so quiet . . . make some noise.”

Frisk’s flush darkened at the insinuation. They couldn’t help if they weren’t very vocal, but there was nobody around but the two of them tonight. And they had been waiting a long time to get Sans like this with them. They ducked their head and pressed themselves further into the pillows on the bed, their hands coming to grip at the sheets. “M-move.” They commanded shakily.

Sans did as commanded, watching his lover with focused eyes. He took in the sight of Frisk’s sweaty skin and the hitch of their breath with each forward thrust in order to save everything for later. He didn’t want to forget a single detail. The intense focus was one of the only things keeping him from finishing too early as he fought against losing himself in the sound and sensation of their sex.

“Harder.” Frisk commanded again as a leg hooked tremulously over his hip. Sans grabbed and held it, pressing further into them at the new angle. Frisk’s voice went momentarily high, and Sans huffed a laugh. Frisk glared at him balefully, but Sans’s smile was too large for them to really be displeased with him. Especially when his movements caused him to brush something nice in them. “Good.” Frisk tried to continue with their “show”, arching their chest and stretching their arms up to grab onto their pillow. “Sans, it feels . . . good.”

“same from here.” He responded, his voice a bit strained. The sight of Frisk with their eyes clenched and mouth lax to pant was knocking the very breath out of him. Everything about the moment was better and worse than his dreams or imaginings. He couldn’t have possibly imagined the scent or the sounds. The strangled whimpered they would occasionally slip from his throat unbidden or the glazed look in Frisk’s brown eyes as they met his. The kid was quickly forgetting they were supposed to be giving Sans a show, but the way their freckles stuck out on their darkened cheeks and the way they gasped his name were more than enough to make up for it.

Sans couldn’t help but chuckle to himself. Just earlier he had been considering the possibility that Frisk wasn’t even interested in sex, and now here he was deep within them. “shit. kid ya probably . . . don’t know but i –lift your hips a bit, frisk– been waitin’ to get you like this for . . . a long time.” He confessed to them.

Frisk reached out and ran their fingers into his hair, grabbing the back of his head. “Me . . . too.” They said before they bit down on their lip, suddenly overcome with some movement. Sans made sure to repeat his aim, and Frisk rewarded him with a tiny cry. Sans kissed them hard, shuddering. It all felt way too good. It was slippery and somewhat disgusting and he didn’t want to stop as he chased his edge. Only the more sensitive part of him nagged about Frisk as well.

Sans startled as he slipped out of them and momentarily felt annoyed with himself as Frisk made a small protesting noise. “sorry,” He murmured to them as he corrected his mistake and pressed back inside. He grinned at them with a quick wink, “you know how they call me slick. guess it’s appropriate.”

Frisk couldn’t help their small huff of a laugh, wrapping their arms around his neck to pull them down to face. They pressed their foreheads together, which only made Sans’s grin broaden at the smile on their face. “What does that even mean?”

Sans kissed their cheek. “don’t matter.” He murmured. “old saying.” He kissed their lips instead slowly, licking into their mouth under the impression of a suggestion. Frisk closed their eyes with a sigh as they allowed the pause. It was difficult for them to properly kiss him while they were bent practically in half, but it didn’t stop them from trying. Nonetheless they weren’t going to be distracted. The burning in their hips and the itch in their stomach needed to be scratched. Their body was trembling from constant build-up and anticlimax. They squeezed their legs and pressed themselves further onto their boyfriend’s cock, insistent and without words. Sans responded with a sharp thrust that had Frisk breaking the kiss with a gasp before he quickly found a rhythm that had Frisk clutching at anything they could.

Their hands groped at his shoulders, nails digging in only for one hand to flutter to his chest. Sans kissed their parted lips briefly as his arms ducked to support their hips, pressing his face into their neck as he shuddered and resisted the call of his own orgasm. He nipped at the skin of Frisk’s neck as he grumbled, “for someone who is . . . so close . . . you’re takin’ a long time. th’hell kind of stamina you got?”

“Maybe you’re just not good?” Frisk teased, and was promptly bitten in reprimand. They gave a small cry. That would bruise. They probably deserved that. Sans definitely wouldn’t want to think about Chara in bed and that was definitely a Chara-influenced comeback. “It’s just . . .” Frisk swallowed against another embarrassing sound as Sans found a lovely spot on their neck to mouth at. They could feel his arm trembling as he shifted to better support himself, adjusting their bodies accordingly. “It’s not . . . enough. And I . . .” Frisk stopped, unable to form a full sentence. Instead they bowed their hips and dropped their arm to grip their pillow as their second hand came down to dance a familiar desperate pattern over themselves. The groan they let out at the slick of their activities slipping over their fingers made their legs clench, meeting Sans’s next thrust. They both had to adjust themselves again to Frisk’s hand being down there to join the party, but Sans only laughed against their skin, ducking his head to watch.

Frisk’s neck arched, arousal spiking to a new level at the double level of stimulation. They were saying nonsense, they knew, unable to control themselves as their edge hardened and approached too quickly. Their stomach tightened almost painfully, only partially aware of Sans’s name slipping from their mouth in a desperate mantra before suddenly the wave broke and they were lost.

Sans’s hand gripped the sheets as his jaw clenched against the feeling of Frisk’s orgasm. Some part of him manically thought about how strange it was before his second orgasm punched through him, leaving him breathless at the suddenness of its arrival. He could only hang on as he was lost in the tidal wave, burying his face into the pillow next to Frisk’s head. His hips stuttered before finally deciding to press into them as much as they could and stop, shuddering.

His brain had temporarily stopped working as his body moved on autopilot, pulling out of Frisk and collapsing next to them as his trembling limbs refused to support him anymore. Sans was seeing stars, and it took him a couple of long moments to realize he was literally seeing stars and then a minute longer to process why there were stars in his bedroom. Then he began to laugh at his own slowness. His mind never moved this slow. It was a novel moment. The giddiness filled him.

“What are you . . . laughing at?” Frisk’s voice broke through the cotton of his mind and he turned his head to look at them. They looked rather blissed out, Sans thought, which did a significant number to his ego and added a new edge to his delight. His hand groped around for their arm before he rolled over to face them, eyes drooping with sudden fatigue. His legs struggled to even move. Maybe he was bit too out of shape for all of the sudden exercise.

“nut’in jus’ . . . stars.” He murmured. Frisk laughed.

“What?” They asked, amused at his slurring.

“shut it.” He grumbled instead, letting his eyes fall closed. The chill of the room was starting to set in, but he didn’t feel like grabbing his blanket. Frisk may be his lover, but Sans was never one to resist the call of his mistress, Sleep.

Frisk grabbed the blanket instead, unable to sleep with the shivering of their body. Their hips ached pleasantly, and Frisk shifted their legs to make a face at the sliminess of their body. They could already see that Sans was well on his way to an abrupt nap, and honestly they should have expected that. They allowed themselves a few moments of just sitting, staring at their body as their fingers gently brushed over their stomach and lower. Everything was sore and sensitive and stretched (they were certain they would feel this when they woke up), but they were pleased. Their plan had succeeded. Which was nice considering they had a history of their plans relating to Sans failing.

They shifted their legs again, shivering at the sensation that pulsed weakly through them, before they collapsed back onto the bed, yanking the blanket up and over both their body and Sans’s. His snores were already beginning to rumble from him signifying he was well and truly passed out. A small part of Frisk was proud of that.  _ They _ had done that to him.

Still the annoyances of their body were beginning to break through the endorphins as their bladder complained and the taste in their mouth became a bit unpleasant. Frisk considered getting out of bed and going to the bathroom, staring up at the stars and planets above them, but their eyelids were drooping and their body still craved the warmth of their lover. Frisk rather thought they deserved post-coital cuddling.

They wrapped themselves around Sans, nosing their way under his chin and tucking their face into his neck. A giddy smile broke upon their face then. They’d had sex with Sans! It was a moment to remember, despite the hiccups and the clumsiness of their first time. They closed their eyes already considering what to do when they both woke up soon. There was so much more they wanted to do with Sans before the night was over. They were excited to have the opportunity to do it with their childhood crush and best friend.

“Stars.” Frisk whispered, their voice breathy and a little more emotional than they wanted. They laughed at themselves. “I love you, Sans.”

Sans didn’t respond, but Frisk took his snores as a good sign. They would tell him again when they were both awake.


End file.
